GBTIDL Files

GBTIDL Release Notes Version 2.9

    Introduction
    Getting Started
    New Index Format
    New Features
    Bugs Fixed
    Register as a GBTIDL user
    Running GBTIDL in Green Bank, Socorro, or Charlottesville:
    Running your own copy of GBTIDL
        IDL License
        Download and Installation of GBTIDL 

Introduction

We are pleased to announce the release of GBTIDL, version 2.9.

As of September 24, 2013, GBTIDL at all NRAO sites corresponds to version 2.9 
and includes the changes described in this note.

Getting Started

    The starting point for GBTIDL documentation, bug reporting and tracking, 
and discussion is http://gbtidl.nrao.edu/
    A comprehensive User's Guide is available. 

New Index Format

    As described below, additions to GBTIDL required a new SDFITS Index file 
version change. The first time you open an SDFITS file in the GBTIDL 2.9 the 
accompanying index file is regenerated. A message informing you of that action 
is printed. This should result in no loss of information. All SDFITS files in 
/home/sdfits in Green Bank (the "online" and "offline" location when using 
GBTIDL in Green Bank) were converted to the new index format just prior to the 
release of version 2.9 and no additional index format conversion is necessary. 

New Features

    The User's Guide is moving to the NRAO Science site. It is being 
reformatted and is expected within a few weeks of this release. When it is 
available, the link from the GBTIDL home page will be updated and an 
announcement will be made via e-mail.
    The molecule procedure has been greatly enhanced.
        The list of molecules now comes from the Database for Astronomical 
            Spectroscopy - Splatalogue.
        This list includes over 78000 lines.
        There are 3 new ways that users can select which lines are indicated 
           on a plot when using molecule: formula, name, and elimit. See the 
           molecule reference manual for more information. 
    New features and changes to support the VEGAS backend. See also the sdfits 
      release notes for more information.
        'online' now recognizes VEGAS data. There is a 'vegas' keyword to force 
           the online mode to look at VEGAS data if there are more recent data 
           from other spectral-line backends.
        sdfits writes VEGAS data to multiple SDFITS files in a single directory.
           The entire directory should normally be opened in GBTIDL so that the
           details of which IF and FEED are found where are hidden from the 
           user. online and offline now do that. When the directory is typed in
           by the user at the GBTIDL command line, either filein or dirin can 
           be used. When the file selection GUI is to be used (by not entering 
           a file path as an argument) then dirin should be used when the goal 
           is to select a directory (e.g. VEGAS data) and filein should be used
           when the goal is to select a single FITS file (other backends).
        The data index file now has a wider SAMPLER column to accomodate the 
           longer SAMPLER names possible from VEGAS. Existing index files will 
           be automatically converted by GBTIDL to the new index format when 
           the accompanying SDFITS file is opened (even if that SDFITS file 
           comes from older versions of SDFITS).
        The standard calibration routines involving two scans now support scan 
           pairs with different numbers of integrations (getnod, getps, 
           getsigref). Formerly, these routines required that both scans in 
           the pair and both beams for the getnod procedure had the same number
           of integrations. During commissioning with VEGAS, this is not always
           the case. These routines now average the appropriate reference 
           integrations when the number of integrations differs and the average
           is then used as needed to calibrate the signal integrations. These 
           routines have a new avgref or avgoff (getps) keyword to force this 
           behavior in the case where the number of integrations do match.
        A new DOPPLER_FREQUENCY data container field. This is the frequency 
           that was used during doppler tracking. 
    New features and changes to support the 69 to 92 GHz receiver (W-Band).
        New data container values: TWARM, TCOLD, CALPOSITION, and QD_METHOD.
        New index column (can be selected on): WCALPOS (equals the CALPOSITION 
           value).
        gettp has a new wcalpos keyword to allow selection on the CALPOSITION 
           table position value (W-Band data). 
    gettp has a new subref argument so that selections can be made on the 
           subreflector state (subref_state).
    The structure returned by scan_info has been enhanced to make it more 
           useful for VEGAS and W-Band processing.
        N_SAMPINTS the number of integrations for each SAMPLER (N_INTEGRATIONS 
           is now the maximum number of integrations [needed for VEGAS]).
        N_WCALPOS, WCALPOS the unique CALPOSITION table values for this scan.
        Note that not all combinations of IFNUM, FDNUM, PLNUM will be present 
           in a given scan. 
    New QuadrantDetector fields in the data container: QD_EL, QD_XEL, QD_BAD. 
        These are used by the new qdflag procedure (which has not yet been 
        rigourously tested and should be used with some caution).
    New PROCTYPE and PROCSCAN data container fields (see MR8Q312 for more 
        details).
    New setfframe and dcsetfframe procedures to change a data container to a 
        different internal reference frame. Normally the reference frame is 
        kept as TOPO internally and the appropriate frame is used during 
        plotting by looking at the velocity_definition field. When saving a 
        data container it is often useful to set the internal frame to match 
        that in the velocity_definition (or any other value) so that readers 
        who aren't familiar with all of the SDFITS convention used by GBTIDL 
        are more likely to know what the intended x-axis is.
    New scalarSubNod contributed procedure 

Bugs Fixed

    gettp When used on frequency switched data without specifying a sig_state 
        only half of data would have been averaged.
    scan_info No longer assumes that the index file is time-sorted.
    summary Provides a better summary when duplicate scan numbers are present.
    bdrop and edrop when an illegal value was supplied the user was not 
        returned to the top-level prompt.
    dcascii there was a fatal formatting error when formatting some velocities
    gmeasure fixed in bug in formatting a warning message when a single channel
        is inadvertantly selected. 

Register as a GBTIDL user

    Use the on-line registration form. 

Running GBTIDL in Green Bank, Socorro, or Charlottesville:

    At the Unix prompt, simply type gbtidl 

Running your own copy of GBTIDL

IDL License

    You must have an IDL license to run GBTIDL. IDL version 6.1 and later is 
supported. If you don't have a license you can run GBTIDL remotely, using the 
computers in CV or GB. See the GBTIDL homepage for details. IDL 6.3 or later 
is needed for large file support on a Mac. 

Download and Installation of GBTIDL

    To obtain GBTIDL, download the files here
    Create a directory for the installation and unzip the tar ball:

        mkdir mygbtidl
        mv gbtidl-2.9.tar.gz mygbtidl/.
        cd mygbtidl
        gzip -d gbtidl-2.9.tar.gz
        tar -xvf gbtidl-2.9.tar

    go to the newly created installation directory, 'gbtidl':

        cd gbtidl

    copy the file 'run_gbtidl' to 'gbtidl':

        cp run_gbtidl gbtidl

    edit the 'gbtidl' script to use the correct path to your installation of 
idl. For example:

        LOCAL_IDL=/usr/local/bin/idl

    edit the 'gbtidl' script to replace "PLACE_INSTALLATION_DIR_HERE" with the 
full path to the gbtidl executable script. It should then look something like 
this:

        export GBT_IDL_DIR=/home/mygbtidl/gbtidl

    start GBTIDL:

        ./gbtidl

    You may wish to add the installation directory to your Unix path. 

-- BobGarwood - 2013-09-23